SJ23 Tech Tip F38, (Created 2021-09-02) Bob Schimmel, Greg Overton (UNDER CONSTRUCTION)


Mainsail Cover - Conventional and Stack Pack.

CONVENTIONAL COVER - A mainsail cover of Sunbrella prevents UV damage to the sail when isn't used.  It also prevents birds from pooping on the sail!  Many sailors customize their cover with the name of the boat.  I much prefer to cover the mainsail than remove it from the boom after each float.  As the expression goes: "It's definitely the lesser of two evils." 
  • The fabric must be water proof and able to breathe so the sail can dry.  Use Sunbrella or equivalent.
  • The bottom should be open between the SS snaps to let the sail breathe.  Having said this, it is not unusual to be sprinkled with water when hoisting the mainsail.  I seldom pack the mainsail when wet but sometimes it is unavoidable.
  • The most forward SS snap is located about a foot behind the mast to ensure the wind does not open it.
  • The most aft SS snap is located at the very end of the cover to prevent the fabric from flapping to death.
  • The cover should be able to stand up to a very strong wind.  Although, a few times I've rolled a line around the cover, spiral fashion, to secure things.  In hurricane strength wind I suggest removing the boom with mainsail cover on it, then slide the whole works into the cabin.  I've had to do this twice with Panache.  It's the quickest and easiest protection to ride out a vicious storm.

DON THE COVER - I place Panache's rolled up cover over the boom just behind the mast, similar to throwing a saddle on a horse.  The top straps are knotted in front of the mast just above the raised spinnaker ring.  The internal flap is folded against the mast to protect the anodized finish from the zipper which is done up (bottom to top).  The bottom straps are tied under a cleat to tension the front a bit.  Then the cover is unrolled towards the end of the boom and the end straps are tied around the boom, tensioning the cover a bit to smooth the wrinkles.  Finally the SS snaps along the bottom are done up.

I also set the main sheet to starboard secured with a line tied to the rail pulling against the main sheet to keep the boom from swinging.  The topping lift keeps the boom just above my head.  I board the boat from port. 

The internal protection flap.

Bottom straps under the cleat.

End of boom straps.

A neat cover can withstand lots of wind.

DOFF THE COVER - Is the reverse of donning it.  The sail cover is usually rolled up from the aft end and stored on the forward berth while underway. 

In 2022 I finally replaced the short aft strap with a longer one that straddles a weak seam.  The end of the strap now includes a SS ring to minimize wear.  At the date of this writing Panache's cover is at least 45 years old.  I've added a few bit and pieces over the years to improve it, but nothing else.  The cover gets washed every few years in a water proofing solution and loose stitches are replaced.  It has survived so many storms that I lost track.  This is the one redeeming property of it.  Look after yours. 

STACK PACK - A stack pack is an improvement on the mainsail cover since all you have to do is pull the zipper along the top to expose the mainsail for hoisting.  This speeds deployment and more important, speeds dousing for inclement weather.  If its quick and easy to do you are more likely to cover the sail to protect it. The covers stays on the side of the boom while sailing so you don't have to pack it away. 

Sloppy stack packs flop in the breeze, which can be annoying while sailing.  The better designed stack pack can be pulled tight against the boom so it doesn't flop around when sailing. 

The lazy jacks typically hold up each side of the stack pack with the assistance of a PVC rod through the hem along the top.  This makes catching the mainsail slick and pulling the zipper along the top easy.  The downward slope to the end of the boom sheds rain, albeit into the cockpit. 

Closing the front was problematic with the early versions as they would catch wind.  Experimenting with different techniques has solved this problem with designs that wrap around the mast as shown in the example at right.  Other designs tuck it on the mast.  The wrap is usually tucked inside one side for sailing.  On some designs it is removed.

This one looks like a Sailrite design.















If you look carefully, the front portion that wraps around the mast, is the only part that detaches.  The remainder stays on the boom as part of the lazy Dutchman system.  Its a clever design that makes it quite easy to don and doff for one person.  No more stretching the cover to the end of the boom.  Only one zipper from what I can tell.

I think the label reads AF Sails.



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